Self-restoring alarm system



March H T941 R ms 2234,940

SELF-RESTORING ALARM SYSTEM Filed Jan. 7, 1938 2 Sheets-Sheet l HM M I'WI'I HOPKINS SELF-RESTORING ALARM SYSTEM Filed Jan. 7, 1958 2 Sheets-Sheet 2 KNVENTOR i lllmlmm lllllllll gfi Mm- BY Patented Mar. 11, 1941 UNITED STATES PATENT OFFICE SELF-RESTORING ALARM SYSTEM Application January 7, 1938, Serial No. 183,748

13 Claims.

The present invention relates to an improvement in alarm circuits of the automatic signalling type wherein constant supervision occurs and wherein fire and similar alarms may be transmitted to a central station indicator from plural subscribers or loop circuits, upon occasion of an alarm condition arising.

The important feature of the present device lies in the provision of means in such alarm circuits whereby any break or short circuit therein may be instantly and. automatically recorded at said central station and the broken section of the circuit automatically short circuited or cut out of the line, thus restoring and closing the unbroken normal section of the loop circuit or circuits and permitting, substantially, continuous, supervised operation of normal portions of the circuit.

This improvement eliminates the risk and danger of an open, non-supervised circuit operation to all of the subscriber stations or loops due to trouble in one loop or section thereof, and the restoration is easily and automatically accomplished at the central station.

The present improvement is of particular value in connection with automatic fire alarm and sprinkler control circuits where as many as twen ty subscribers or stations are connected into a single loop circuit.

The foregoing and other features of advantage will be apprehended as the herein description proceeds and it will be obvious that modifications may be made in the system herein disclosed without departing from the spirit hereof or the scope of the appended claims.

In the drawings- Fig. 1 is a diagrammatic layout of an automatic fire alarm circuit in normal operative condition;

Fig. 2 is a view similar to Fig. 1, but disclosing the circuit in the act of cutting out a broken loop;

Fig. 3 is a diagrammatic layout of a modified form of fire alarm circuit;

Fig. 4 is a fragmentary view, in perspective of a trouble indicating device and break down resistance; and

Fig. 5 is a View in elevation of the device of Fig. 4, with parts broken away to show the mechanism thereof.

In Fig. 1, a main source of electric current B is connected to a main conductor l, which is connected at its opposite end to an electric relay switch contact k. A second main conductor 2 is connected to the oppositepole of said source B, and to a code alarm receiving and recording apparatus P and at its opposite end is connected to an electric relay switch contact or Contact 9 is in normally closed contact with a relay switch e, and this in turn, by conductor 22, connects to one terminal of a slow acting magnet 5, which in turn, at its opposite terminal is connected by a conductor 3 to a subscribers loop circuit FA-24--FA-52--FAG, relay operated switch contact k, relay switch 71. and, through conductor I to source B. This latter circuit constitutes a normally supervised and closed, operative series alarm circuit. The elements FAFA--FA", in the subscribers loop circuit may represent code signalling fire alarm boxes, or other alarm devices.

Between the FA loop circuit conductors 3-4 and 4-5 and 4-6 are mounted a series of insulated breakdown resistance elements, W---W and W" which, Figs. 1 and 2, while normally bridging said conductors, pass no current. These resistances may be of varying voltage breakdown capacities, but in every event, the breakdown capacities of these resistances are higher than the main circuit voltage and some are higher in resistance, relatively, to each other, as will later be explained in detail.

When the alarm circuit is operative, as in Fig. l, the slow acting magnet 5 is energized, and this draws up the relay switch a and normally holds it out of contact with switch contact 1). Slow magnet 5, being slow to operate to open or close relay switch a, does not function upon operation of code alarms from the stations FA, because the code alarm interruptions of the circuit are too fast, and thus the main line and loops remain substantially constantly in operative connection with the current source B, even during operation of code alarms. As such alarms come in, they are picked up by the central station receiving or recorder apparatus P, in the customary manner.

There are a cascade of three additional slow acting relay magnets 6, I and 8, these being located in separate, successively operated branch circuits which will now be described.

Contact a, which is normally held out of contact with switch contact b is connected by conductor I to one terminal of an auxiliary current supply source b, the other terminal of source b being connected by a conductor 8--lll to a normally open relay switch m.

Conductor 8 and source b are connected to a normally open relay switch 1', by conductor 9, one end of which is connected to one terminal of slow acting relay magnet 6 by conductor 9', the other terminal of said magnet B being connected by a conductor l3 to normally open contact terminal b.

Switch contact 0, which is normally open, is located to close with switch contact d which is connected to one terminal of the next successive slow acting magnet l by a conductor I 4. The opposite terminal of magnet T is connected through conductors l2 and II to the auxiliary battery source b, at the terminal thereof to which conductor 1 is connected.

Relay switch it is so located as to be in normally open position with switch contact 7', which in turn is connected to relay switch r by conductor 20. Relay switch 1" is in closed contact with switch contact t which in turn is connected by conductor l'l to an intermediate terminal t on the high voltage electric current supply source H.

Relay switch r is so located as to be in open non-contact position with switch contact 8 which in turn is connected to the outer terminal s of high voltage supply source 1) by conductors I8 and f9. Said conductors may have connected therein a recording annunciator A, whereby, upon operation of the restoring branch circuits by a trouble loop section later to be described, the trouble operation thereof, and current use, will be automatically indicated and recorded.

Closed switch e is so located as to be in normally open position with switch contact f which in turn is connected to terminal f of high voltage source V, by conductors l5 and it, said conductors having located therein a recording annunciator A, which acts as described for annunciator A, when this leg of the circuit becomes energized by a trouble signal.

Auxiliary source b is connected to a further open branch circuit by a normally open switch m, which is connected to said source by conductors 8 and H].

Slow acting magnet 8 is connected by conductor I l at one terminal thereof, to auxiliary source b. The opposite terminal of magnet 8 is connected to normally open switch contact a. Adjacent switch r is in position relative to magnet 8 to be influenced upon a trouble signal to break 1' from contact 1 and to close with contact 5.

Slow acting magnet 5, upon a trouble signal, influences switch to contact with switch d, thus to energize slow acting magnet 1.

Slow acting magnet 1, upon a trouble signal, influences switches e,.h and m to simultaneously close with switch contacts .1, :i and n respectively, thus breaking contacts with switches g and is.

As the diagram is disclosed in Fig. 1, the main current supply source and the subscribers loop circuits FA are in normally closed operative alarm condition, and are normally under the supervision of the cascade of the slow acting magnets 5, E, i and 8. If a break occurs in, say, at signal box FA or in the line 4 at 0, Fig. 2, all of the FA boxes in the loop 3, 4, '5 and 6 are disabled, and the source B is cut out of the main circuit and ceases to function.

Upon a trouble signal break occurring as above described, the following sequences take place; slow acting magnet 5 is deenergized and releases switch a, which then closes with contact I). This action energizes slow acting magnet 6 from the source b, through the closing of switch 0 with gizes slow acting magnet I from source I), through the closed circuit 8, 9, I l, l2 and II.

The energizing of slow acting magnet I simultaneously acts to close switches e, h and m with their respective open contact I, 7', and 12.

Upon the closing of the triple switches e, h and m with their respective, normally open contacts J, 7' and n, the following actions take placeswitch e closes with contact I and connects with terminal f, of main current source H, on the V side through conductor I5l5. Source V, through terminal I, conductor l'l, closed relay switch fr, conductor 2%, closed relay switch a'h and conductor 6 is then connected to the broken F-A loop 3, 4, 5. The other leg of the broken FA loop is connected to source V by the closing of relay switch fe, through which as previously noted, the terminal 1" of source V is connected to conductors l5, it, 22 and 3. As the normal operative voltage of source B is about 24 volts, the operative voltage of section V of source H may be about 50 volts.

Presuming that the code box FA or its adjacent circuit connections became disabled, and send in a trouble code, which caused the cut-out of source B and the interpolation of source V as above described, and presuming that the resistance break down values of resistance W and W are about 40 volts each, and the break-down value of resistance W is about 80 volts, then, by a break 0 occurring in the FA loop, Fig. 2, the operation of the slow release magnets 5, 6 and l as above described, and as shown in Fig. 2, will first automatically impress a potential of 50 volts on the troubled F-A loop circuit from source V. This will cause the i0 volt resistance element W to short circuit, and bridge the cir cuit at this point, as at X, Fig. 2, thus cutting out signal box FA' and its troubled loop and restoring boxes F-A and FA back into normal, supervised, alarm operating condition in connection with main source B.

When the trouble alarm as above described comes in, one of the annunciator drops 21, of annunciator recorder 21 will drop down as at D, Fig. 2, and thus indicate, and record the trouble. As the annunciator A is in the 50' volt V trouble circuit, the drop 2'l-D will thus help to locate the broken loop, by its operation, showing that 50 volts was utilized to restore the loop circuit.

The current source H, and its indicating and recording devices A and A, like source B and its code signal recording device P may be located at a central station, and upon the operation of the annunciator drop D2'l to indicate an abnormal loop circuit condition, the attendant can hook in a meter in the line at the central station and by the reading thereof locate the particular troubled loop or branch circuit, thereby facilitating the location of the troubled circuit or loop, and its repair.

After the shorting of the resistance element W, Fig. 2, the system sets about to restore the normal code signal alarm operation, back to the central station current source B, as follows:

The time consumed after a line break occurs, to short circuit or bridge the troubled line by the resistance elements is very short. Upon actuation of slow release magnet 1, as previously noted, it operates switches e, h and m simultaneously, and this causes the action of the trouble correcting circuits as previously set forth.

The contacting with contact f, by switch e, causes current to flow through slow operating magnet 5, through the line 22, magnet 5, line 3,

through the FA loop through line 6, through bridged resistance X, through switch it, contact 7', line Eli, switch r, contact t, line I! to terminal ,1" of source V, from terminal I, lines [5 and Hi to contact I, through switch e, thus closing the above noted circuit, sequentially to the bridging of resistance element W". The magnet 5 then slowly becomes energized, and influences switch a to break with contact b, and thus assume its normal operative position with relation to magnet 5, and source B, and this cuts out slow magnets 6 and l and restores their respective switches c, e, f and m to the normal code alarm positions, as disclosed in Fig. 1. This action also cuts out the auxiliary battery b, and the alarm system is again in supervised functioning condition.

Obviously, the foregoing sequence of opera tion is quite rapid, and the time of automatically bridging the broken line and restoring the alarm functions of the system is comparatively brief.

There is one further selective step of operation that may occur, in the event of a break down of the F-A loop system, and that is, when the break in the loop occurs, instead of at W, as above described, at a point between bridging resistance l and W. The resistance of the bridging resistance W being 80 volts, the operation of the magnets 5, 5 and 1 which imposed a potential of 50 volts upon the broken loop as previously described from source V, cannot cause the bridging of the resistance W.

Therefore, by this time slow acting magnet 8, having been sequentially energized by the closing of circuit b, H, 2|, n, m, I and 8 with auxiliary source b acts to break switch 1" from contact 1 and connect said switch with contact 8, thereby closing with current source V-V, and completing the circuit |9l8, to terminal source H (VV) from terminal conductor l5, l6, contact 1, switch e, conductor 22, magnet 5, conductor 3, broken FA loop, conductor 6, switch it, contact 9', conductor 2i), switch r to contact s, thus impressing the potential of the two battery sources V and V upon the broken F-A loop, to a voltage of, say, 100 volts. This causes the resistance bridging 80 volt element W to break down and bridge the break in the FA loop, cutting out those stations F-A" and FA beyond the break, and restoring station F-A intonormal supervised alarm condition.

Immediately after the bridging of the broken loop occurs, the alarm circuit is restored, as previously set forth, by the restoration of the slow acting magnet cascade, to supervisory alarm condition. Thereafter the broken loop circuit is repaired.

From the foregoing it will be thus seen that the present structure not only automatically and substantially immediately restores a broken circuit, but substantially tests, sequentially the broken loop in order to bridge out the troubled portion of a loop, after testing the loop and bridging it inside of the broken portion thereof, at any broken point, after such sequential testing.

It is obvious that the disclosed cascade of slow acting magnets may be added to, so that the control for the troubled loops may be augmented for more than the number F-A stations shown herein.

In Fig. 3 there is shown a slightly modified form of central station control and automatic loop break restoring means, in which the branch lines 38-45 contain plural subscriber's stations L, L, L and L. Across each of the loops are located break-down bridging resistance elements W, W,

W and W, each of these, under normal alarm conditions, passing no current, but which upon the development of a break, in any section of the branch hues 42 or 45, or in the station loops, may be manually shorted from the central station to cause a bridging out of the troubled loop section, and the restoration of the untroubled section of the loop,

To the foregoing ends, the central station is provided with a main current supply source B, and an alarm device S, which may be combined with the usual recording device, not shown, and which device or recorder may be connected to said source B, by conductors 35 and 36. Conductor 35 is connected to one terminal of source B, the opposite end of source B being connected by conductor 31 to one terminal of a jack switch system generally denoted by J. Another jack terminal is connected by conductor 39 to one leg of the branch 39 of the subscribers loop, and through the loop circuit 40, 4| and 42 and through conductor 38 is connected to a terminal of the jack switch J. As thus described, this circuit is a closed series circuit under the constant, supervised alarm operating conditions well known in this art.

In Fig. 3, there is also shown an auxiliary current source generally denoted by H, and comprises two connected sources of different voltage V and V. An indicating recorder or meter A is connected to one terminal of source V and is in turn connected to the opposite terminal of current source V by conductors 4344, there being a jack plug C interpolated in lines 43 and 44. A second jack plug C is connected to one terminal of the source V, said plug being connected to a terminal of recorder A byconductor 44.

Normally the current source and plugs C and C are not operative, but upon occasion of a troubled loop interrupting the normal alarm condition of the loop circuit, the operator-attendant may first insert plug G, into jack J, cuttihg out main source B, which may be of about twentyfour volts capacity.

Source V, may be about fifty volts capacity is thus plugged into the loop line, thus impressing a potential of fifty volts upon the troubled loop line. The bridging resistances W, W, W

and W' may all be of about forty .volts capacity,

and the resistance W may be of about eighty volts capacity. Thus if the break in the loop occurs between the station L and the resistance W, plugging in plug C causes resistance W to bridge the troubled portion out, and restore the untroubled section of the loop, whereupon, withdrawal of plug C restores the line to normal current source and alarm condition.

In the event that the loop becomes troubled and the operator plugs plug G into source V, and finds no corrective response, he then removes plug 0 and inserts plug G into the jack J, and this impresses a potential of about one hundred volts from sources V and V' upon the troubled line, and if the break is between bridging resistance W8 and the stations L" and L', then eighty volt resistance W breaks down and bridges out L and L, and restores stations L and L into connected series, and the withdrawal of plug C restores the stations L and L back to normal closed circuit alarm condition with source B.

In Fig. 3, it will be noted that the break down resistances generally denoted by 50 are diagrammatically shown in a different form than those shown in Figs. 1 and 2. The resistances 50 are more fully illustrated in Figs. 4 and 5, and while they are fully the equivalent, in function with the resistances of Figs. 1 and 2, they are amplified in construction toobtain further functions and features of advantage.

Fig. 4 discloses an indicating signal breakdown resistance mechanism, which is enclosed in a closed cabinet, generally denoted by 50. This mechanism comprises a target or signal opening 55 which is arranged in the front face of cabinet 50, Fig. 4.

Behind the opening, and suitably and permanently mounted in said cabinet is located a wafer break-down resistance element W, the opposite spaced terminals of which, shown dotted, are connected to conductors 5| and 52. Conductor 5|, by means of connector post 63, is connected to conductor 48, which in turn is connected to loop conductor 38, Fig. 3.

The opposite conductor 52 is connected to the winding of a relay magnet M, and the opposite terminal of the winding M is connected to a connector post 54 by a conductor 53. Post 64 is connected by conductor 49 to the loop conductor t2, Fig. 3. As thus described, the break-down resistances WW, W" and W, all of similar construction are shunted across their respective loop lines, but do not conduct current thereacross until broken down by a trouble condition, as previously noted for the break-down resistances disclosed in Figs. 1 and 2'.

As disclosed in Fig. 5, the relay or solenoid magnet M is provided with a suitably supported spring suspended armature 62, normally insulated from the magnet and out of contact with the core by the insulated bracket 56. As mounted in Fig. 5, the armature 62 normally abuts the end of a pivot arm 6| which is suitably pivoted at 6-3, the other end of the arm 6| being provided with a disc-like target T, which, as shown in full line in Fig. 5, is held away from the target opening 55.

Upon a trouble condition arising in the loop circuit, as previously described, the correction conditions of the circuit break-down the resistance wafer W, permitting the shunting of current across said wafer, energizing said magnet, thus to withdraw the armature 62 from the arm BI, and permitting the target T to drop to the dotted position shown in Fig. 5, and be thus exposed before the window 55. The target may be colored, and thus be more easily seen through the window. This break-down resistance indicator may be located as a shunt in its associated loop, or may be located remote from the loop, or at the central station, as may also the break-down devices of Figs. 1 and 2.

The signal or trouble indicator of Figs. 4 and 5, when in any location, is useful in aiding in the location of its associate troubled section of the loop circuit. After the correction of the broken loop section, the broken down resistor W may be replaced with a new resistor, the target T restored to its non-alarm trouble supervising condition, as shown in Fig. 5 in full lines.

It is understood that the trouble indicator of Figs. 4 and 5, with its target means, may be used in any of the loop or branch circuits of Figs. 1 and 2, as a substitute for the break-down resistors therein shown. Thus, in addition to the central station trouble indicators, the subscribers loops may each also be provided with local trouble indicators.

A further method ofascertaining the point of trouble is diagrammatically disclosed in Fig. 5, wherein all of the connections described remain the same, except that the armature 62 is removed, as is also the target T, and the magnet winding N is extended as shown by the dotted extension N and a conductor 5 therefrom connected to terminal 66, eliminating the conductor 53. Thus the winding N-N becomes a series resistance of a given capacity, and when the break down occurs across W, this resistance may be used, with a plugged in voltmeter, to ascertain the location of the break. The indicator A of Fig. 3, may be a permanently installed voltmeter and the reading thereof upon occasion of a trouble signal will indicate the location of the break.

To accomplish this last noted feature, it is, of course, necessary that each series resistance N-N in each loop or branch circuit is of a diiierent, specific voltage capacity, so that when a break down occurs, and a reading taken on A, or an equivalent voltage indicating device, the reading of the indicator will indicate the troubled section or loop, and repairs promptly made.

Having thus described the invention what is claimed is:

1. A signal system comprising a. line loop; a receiver normally adapted to be influenced by line loop current; normally closed code transmitters in the loop; shunts shunting different loop portions and including normally nonconductive breakdown devices of resistance sufficient to resist normal voltage during transmitter operation; and means for applying normal voltage to the line loop, and means set in operation by line loop break for applying to the line, until a device is broken down, increased voltage sufficient to break down a device.

2. A system as in claim 1 including means for restoring the voltage to normal when the line loop is again complete.

3. A system as in claim 1 including indicating means operated by current fiow in the shunt after breakdown for indicating which individual device is broken down.

4. A signal system comprising a line loop; a receiver normally adapted to be influenced by line loop current; normally closed code transmitter switches in the loop; shunts shunting different loop portions and including normally non-conductive breakdown devices of resistance sufficient to resist the normal voltage during transmitter operation; and means for applying normal voltage to the line loop, and retarded means set in operation by current cessation caused by line loop break for after an interval applying to the line until a device is broken down increased voltage sufficient to break down a devic.

5. A signal system comprising a line loop; a receiver normally adapted to be influenced by line loop current; normally closed code transmitters in the loop; shunts respectively shunting different loop portions and including normally non-conductive breakdown devices of different breakdown resistances suflicient, before breakdown, to resist the normal voltage during transmitter operation; means for applying normal voltage to the line loop, and means adapted to be operated during line loop break for applying to the loop until a device is broken down, first an increased voltage sufficient to break down the less resistant device and insumcient to break down the more resistant device and then a still stronger voltage suiiicicnt to break down the more resistant device.

6. A system as in claim 5 including means for restoring the voltage to normal when line loop is again complete.

7. A system as in claim 5 including means for indicating which individual device is broken down.

8. A signal system comprising a line loop; a receiver normally adapted to be operatively influenced by line loop current; normally closed code transmitter switches in the loop; shunts shunting different loop portions and each including a normally non-conductive breakdown device of different breakdown resistance suflicient before break-down to resist normal voltage during transmitter operation; means for applying normal voltage to the line loop, means adapted to be set in operation after line loop break for applying to the line until a device is broken down, first an increased voltage sufficient to break down the less resistant device and insufficient to break down the more resistant device. and means then influenced to operate by the failure of a device to break down, if a device is not broken down, to apply a still stronger voltage suflicient to break down the more resistant device.

9. A system as in claim 8 set in operation by the completion of the loop on such break down for restoring the voltage to normal.

10. A signal system comprising a line loop; a receiver normally connected in the line loop; normally closed code transmitter switches in the loop; shunts respectively including normally nonconductive breakdown devices of different breakdown resistance, the shunts respectively shunting different loop portions; each breakdown device having, before break-down a resistance sufiicient to resist the normal voltage during transmitter operation; means for applying normal voltage to the line loop and set in operation by current cessation caused by line loop break for after a delay applying to the line until a device is broken down, first an increased voltage sufficient to break down the less resistant device and insufficient to break down the more resistant device and then, if a device is not broken down, applying after a delay a still stronger voltage suficient to break down both; devices, and restoring the voltage to normal when the line loop is again complete.

11. A signal system comprising a line loop; a receiver normally adapted to be influenced by line loop current; normally closed code transmitter switches in the loop; shunts shunting different loop portions and including normally non-conductive breakdown devices of resistance sufiicient to resist the normal voltage during transmitter operation; means for applying normal voltage to the line loop, means for applying to the line until a device is broken down increased voltage sufficient to break down a device; and an indicating means for indicating which device is broken down.

12. In a system as in claim 11, said indicating means comprising a trouble indicating means interposed in each shunt adjacent to the breakdown device thereof and operated by current flow in the shunt after breakdown for indicating at the device which individual device is broken down.

13. In a system as in claim 11, said indicating means comprising a trouble indicating means separate from the break-down device and interposed in each shunt adjacent to the breakdown device and comprising a biased member released by current flow in the shunt on breakdown for indicating at the device which individual device is broken down; and means for holding the memher in normal position when it is restored after current in the shunt ceases.

RICHARD M. HOPKINS. 

